Alloy



June 6, 1939. F. R. HENSEL Er'AL 2,161,467Y

ALLOY Filed Ju-ne 15, 1.937 2 Sheets-Sheet l f/v/vfss am.' www MENU/fo ma/560%" /lEo Hr 450%' INVENTOR s F/H/VZ 7E HE/VSEL ATTORNEY June 6, 1939. F, R, HENSEL ET AL 2,161,467

ALLQY Filed June 15, 1937 2 Sheets-Sheet 2 .40 i@ f n@ mf u 7o com fr0/wr ,Wm/46m@ bq K f duf/wam fnv/v 950 'c 9 650 .i2/100m 450% v; 40 o 0 zu 40 A o Jaa 1z0 daf/vm@ man 950 c H650 fir 450 g o- @afslaan/wry U 20 40 60 80 100 12v am FEM/(770V PER c'E/v ATTORNEY 'Patented June 6, 1939 Y UNITED STATES Alm! y Franz R.. Hensel and Earl I. Larscm Indianapolis,

Ind., assignors to'P.

R. Mallory & Co., Inc.,

Indianapolis, Ind., a corporation of Delaware Application June 15, 1937, Serial No. 148,283

2 Claims.

This invention relates to alloys, and more particularly to copper alloys of improved characteristics. The object of the invention is to produce an improved copper base alloy.

Another object is to produce a copper zinc a1- loy of comparatively low zinc content, which can be hardened by means of the addition of a small percentage of zirconium to a higher degree than has heretofore been possible.

Another object is to produce a copper alloy which has an excellent combination of hardness, electrical conductivity and resistance to anneal- Further objects are to produce alloys which are readily handled in the mill having a high degree of fluidity in the liquid state and producing sound, clean billets, which are ideally suited for further manufacturing, showing no tendencies of season or fire cracking.

Specific objects are the provision of improved copper-zirconium-zinc alloys especially suitable for fabrication into welding electrodes, high strength sand castings for use with cylinder heads, pistons and other parts of internal combustion engines, commutator segments, trolley wires, collector rings, switch plates, bolts, nuts and in general for all uses where high strength and/or high conductivity are required at elevated temperatures. l

Other objects of the invention will be apparent from the following description taken in connection with the appended claims.

The present invention comprises a. combination of elements, methods of manufacture and the product thereof brought out and exemplified in the disclosure hereinafter set forth, the scope of the invention being indicated in the appended claims.

In the drawing:

Figures 1, 2 and 3 are graphs showing curves illustrating the improvement during age hardening in the hardness and electrical conductivity of alloys containing various percentages of zirconium and zinc as follows:

Figure 1- Per cent Zirconium 0.48 Zinc 0.62 Copper Balance Figure 2 Zirconium 0.85 Zinc 0.55 Copper Balance Figure 3- Zirconium 0.97 Zinc 1.79 Copper Balance Figures la, 2a and 3a are graphs showing the effects of cold working of the alloys referred to in Figures 1, 2 and 3, respectively, after age hardening.

While a preferred embodiment of the invention is described herein, it is contemplated that considerable variation may be made in the method of procedure and the combination of elements,

without departing from the spirit of the invention.

Alloys of copper and zinc in various proportions have been made and used commercially for many years. These alloys in the cast form are quite soft and can only be hardened to a very limited extent by cold working. As a matter of fact, a zinc alloy containing 5% zinc, known generally as gilding metal, can not be work hardened appreciably harder than pure copper. Furthermore the increased hardness can only be retained at fairly low temperatures. If these al- Per cent Zinc 0.1 to 10 Zirconium 0.1 to 5 Copper Balance It is possible likewise to improve the characteristics of other copper zinc alloys containing small percentages of additional ingredients by the addition of zirconium. 'I'hus copper zinc alloys containing small proportions of silver, cadmium, calcium, lithium, silicon, aluminum, magnesium, titanium or beryllium can be improved by the addition of 'zirconium in substantially the proportions indicated above. f

The addition of zirconium to the above alloys renders them susceptible to age hardening.

The alloy can be made according to standard alloying methods', A preferred method of alloying is to prepare a hardener alloy containing l50% zirconium and then introduce a predetermined amount of this alloy into a copper zinc alloy of the desired composition.

After the alloy has been prepared according to the standard alloying methods the heat treatment may be carried out as follows:

The alloy in the form of a billet or any other form, such as a sand casting or a rolled, forged or extruded bar, is raised in temperature to above '700 C. and preferably to a temperature in the order of 700-1000 C. The alloy is then quenched from this high temperature and subsequently temperature or a shorter time may be employedaged at a temperature below 700 C. and preferably in the range of between 40o-600 C. This heat treatment results in a considerable improvement in hardness. of the alloy, as can be seen from the figures. l. y

We have also found that we can quench the alloy in any desirable form and then apply a certain amount of cold working. Alloys of the nature described have been found to be particularly suitable for cold working in the quenched condition. While the alloy, after quenching, will show a minus Rockwell B hardness, cold working after quenching might raise this hardness to aRockwell B number in the neighborhood oi' -70. After this cold working operation, the material is aged in the range between 35o-600 C. Due to the cold working after quenching, a lower for the aging operation, thus bringing about a material reduction in cost of manufacture, when compared with the usual long drawn out aging operations.

After aging, the material can be still further hardenedby applyingco`ld work up to reduction in area. The above described treatments consisting in heat treatments and mechanical workings, have a remarkable eifect on the electrical conductivity, as shown in Figures 1, 2 and 3. `Values of electrical conductivity ranging from 65-85% can be readily obtainedy within the percentage ranges given.

This alloy is therefore wellI suited for use at comparatively high temperatures since hardness and electrical conductivity are maintained for indefinite periods at the aging temperatures indicated.

It was found that the alloys can be cold worked after complete aging as much as -90% without losing more than 1-2% in electrical conductivity. 'I'his makes the alloy particularly suitable for severe drawing operations, and forA use in wire remainder copper.

2. A pressure exerting electrode composed of form where high strength and high conductivity is required, such as for instance, trolley wire.

`'Ihe alloys prepared as indicated are well suited f for a large number of purposes. They may be used in the form of sandl castings, chill or permalnent mold castings, forgings, rolled, extruded or drawn stock, for such applications as commutator segments, collector rings, switch plates,

bolts, nuts, and for all parts where special electrical requirements or high heat conductivity and resistance to high temperatures are needed.

The alloys are especially adapted .for fabrication into resistance Welding electrodes, such as spot Welding tips, welding Wheels, ash Welding dies, etc.

Since the addition of zinc makes the alloy quite fluid, it is very well suited for high strength sand castings, such as cylinder heads, pistons and other parts of internal combustion engines, suchas automobile engines, where high heat conductivity is needed.

While the present invention, as to its objects and advantages, has been described herein as carried out in specified embodiments thereof, it is not desired to be limited thereby, but it is intended to cover the invention broadly within the spirit and scope of the appended claims.

What is claimed is:

y1. A pressure exerting electrode composed of about 0.1-10% zinc, 0.15% zirconium, and the about 0.1-10% zinc, 0.1-5%'zirconium, and the -remainder substantially all copper, characterized by a combination of high hardness and high electrical conductivity, and further characterized by the ability to maintain its hardness and high conductivity at temperatures in the order of FRANZ R. HENSEL. EARL I. LARSEN, 

